1. Field of the Invention
The present invention relates to a radial tire for aircraft.
2. Description of the Related Art
Tires for aircraft are required to have sufficient durability to withstand high-speed and heavy loads since they are subjected to a large impact (fall) at high speed at the time of the take-off and landing of the aircraft. In addition, since present-day aircraft frequently taxi a relatively long distance in airports, tires for aircraft are required to have high performance in terms of both durability and traveling performance during taxiing in the same way as tires used for general vehicles.
For this reason, it has been conceived to use radial tires as aircraft tires by taking into consideration various performances such as wear resistance, heat resistance, and fatigue resistance against repeated loads, as well as various conditions such as weight and cost.
Under conditions of use in which a large strain takes place in tires such as aircraft tires, it is known that a portion of the tire abutting against a rim flange is liable to undergo friction by the rim flange and become worn. This phenomenon is liable to occur more frequently in the case of radial tires than in the case of conventional bias-ply tires.
As a means for overcoming the wear of the abutting portion caused by the rim flange in the case of radial tires, a method generally adopted is to reinforce a portion of the carcass located close to the rim flange. In accordance with this method, the weight of the tires increases, so that it is not a desirable method for aircraft tires that are required to be reduced in weight.
In addition, with the tires having a carcass including an up carcass layer and a down carcass layer, since the up carcass layer is wound around a bead core from inside towards outside and the down carcass layer is wound around the bead core from outside towards inside, this structure is effective in preventing the carcass layers from being pulled off for the tires used under high inflation pressure. However, with the tires of a type having a carcass with this structure, carcass-reinforcing cords are likely to undergo fatigue in the vicinity of the bead portion.